The assembly of certain structures requires the ability to adjust the length of one or more structural members to accommodate manufacturing and assembly variations and thereby allow the members to be connected to mating structures. For example, the propulsion units (e.g., the gas turbine engines) of a commercial aircraft may be attached to the wings by means of nacelle struts. Each nacelle strut-to-wing installation may involve the use of a diagonal brace and a collection of links to pin the nacelle strut to the wing. Each link has opposing ends with a link bore in each end. A first upper link may initially be installed to connect a strut fitting on the top of the nacelle strut to a wing fitting on the wing front spar. The diagonal brace may then be installed to connect a strut fitting on the lower aft end of the nacelle strut to a nacelle support fitting on the lower surface of the wing. A preload may be applied to the nacelle strut to adjust the distance between the strut fitting and the wing fitting to match the center-to-center distance between the pin bores of the diagonal brace such that pins may be inserted into the pin bores to couple the diagonal brace to the fittings.
The installation of the first upper link and the diagonal brace results in a highly rigid system. Unfortunately, the high rigidity of the system complicates the installation of the second upper link. Because of the above-mentioned manufacturing and assembly variations and because of loads on the system, the center-to-center distance between the pin bores of the second upper link may not be the same length as the center-to-center distance between the strut fitting and the wing fitting. The mismatch in the center-to-center distance of the second upper link relative to the strut-to-wing center-to-center distance may prevent the installation of pins into the corresponding bores of the link and the strut and wing fittings. The high rigidity of the system may prevent further preload on the nacelle strut to adjust the center-to-center distance between the strut fitting and the wing fitting to allow the second upper link to be installed.
As can be seen, there exists a need in the art for a means for providing adjustability in the connection of a structural member to a mating structure. For example, there exists a need in the art for a means for adjusting the center-to-center distance between the bores in opposite ends of a structural member so that the structural member may be attached to the mating structure at each end of the structural member.